In a wireless communications system, transmissions are generally communicated in accordance with pre-defined fixed frame structures. Fixed frame structures are used so that communicating devices have knowledge of resources, such as time, frequency, or time and frequency resources; and interferences between different resources and between transmitting and receiving of signals may be avoided or reduced. Modern wireless networks are increasingly used to support communications of diverse traffic types. Different traffic types may have different characteristics and quality of service (QoS) requirements, such as latency, which fixed frame structures may be unable to accommodate. Accordingly, adaptive frame structures capable of efficiently supporting different traffic types are desired.